Surface-mountable piezoelectric devices are preferably manufactured by mass-production. In the piezoelectric device disclosed in Japan Unexamined Patent Document No. 2006-148758, a quartz-crystal wafer having a plurality of quartz-crystal vibrating pieces is sandwiched between a lid wafer and a base wafer, wherein all three wafers have the same shape. Also, in the methods for manufacturing piezoelectric devices as disclosed in Japan Unexamined Patent Document No. 2006-148758, through-holes are made on the lid wafer and the base wafer for each corner of a package lid and a package base. An edge wire is formed on each device for electrically connecting the respective excitation electrodes with respective external terminals on each corner of the piezoelectric device. Then, the piezoelectric devices manufactured on the wafer are separated into individual pieces.
However, in the method of Japan Unexamined Patent Document No. 2006-148758 for manufacturing piezoelectric devices at a wafer scale, the through-holes are situated on each corner of a piezoelectric device, the adjacent piezoelectric devices remain as one unit. Whenever a piezoelectric device is cut along an edge, load is applied onto the piezoelectric device, and causes damage to the piezoelectric device. Also, the adjacent excitation electrodes of the adjacent piezoelectric devices are electrically connected by edge-surface electrodes formed on the through-holes. Therefore, the vibration frequency produced by individual piezoelectric vibrating pieces on the wafer cannot be measured.
In view of the foregoing, the present disclosure provides piezoelectric devices in which each piezoelectric device is less likely to be damaged during the cutting process into individual piezoelectric devices. The vibration frequencies of a plurality of piezoelectric devices on the wafer can be measured without being affected by adjacent piezoelectric devices. The present disclosure also provides methods for manufacturing such piezoelectric devices.